Flower Visiting Flies (Insecta: Diptera) and their Interaction with The Flowering Plants in a Tropical Island Ecosystem
Keywords:Insect-plant interaction, bipartite network, island agro-ecosystem, flower-visiting Diptera, Syrphidae
Pollen transportation and pollination is an essential ecological function. Flies of order Diptera perform a significant role in transfer of pollen and pollination to some extent (Raguso, 2020). In tropical island ecosystems the flower visiting dipteran flies may function simultaneously with the bees to maintain a healthy ecosystem service. However, the study of flower visiting Dipteran flies in India has received less attention from the entomologists and even lesser in island ecosystems. In tropical areas the Hymenopterans can be outnumbered by the Dipterans in terms of biodiversity (Inouye, 2001). So, the main objective of this study is to identify and make an inventory of flower visiting Dipteran flies of a tropical island along with their visited plant species. The study was conducted across the Sagar Island, West Bengal. The collection of flies and observation of the plants visited by them was done through line transect method in 10 chosen study sites containing both the crop and non-crop flowering plants. Throughout the study, a total of 41 species of flies belonging to 34 genera under 13 families have been observed to visit flowers of 32 species in our studied landscape. Paragus (Paragus) serratus of family Syrphidae has been found to be the most interactive fly visiting 27 different flowering plant species and Mangifera indica appears to be the most visited plant with 17 dipteran species visiting its flowers. We have also observed the variation in seasonal occurrence of the flower visiting flies and prepared a simple bipartite network representing the links between the dipteran flower visitors and their visited flowering plants. The outcomes illustrate a clear scenario of flower visiting Dipteran flies occurring in a tropical island which interact with the plants. This can also lead to future studies about pollination by Diptera in an island ecosystem.